Buggy code:
public class AutolinkTest extends TestCase { private static Log log = LogFactory . getLog ( AutolinkTest . class ) ; private MockWebApplication application ; public AutolinkTest ( String name ) { } public void testRenderHomePage ( ) throws Exception { } private boolean validateDocument ( String document ) { System . out . println ( document ) ; HtmlDocumentValidator validator = new HtmlDocumentValidator ( ) ; Tag html = new Tag ( "html" ) ; Tag head = new Tag ( "head" ) ; html . addExpectedChild ( head ) ; Tag title = new Tag ( "title" ) ; head . addExpectedChild ( title ) ; title . addExpectedChild ( new TextContent ( "Mock<seq2seq4repair_space>Page" ) ) ; Tag body = new Tag ( "body" ) ; html . addExpectedChild ( body ) ; Tag anchor1 = new Tag ( "a" ) ; anchor1 . addExpectedAttribute ( "href" , ".*MockWebApplication.*" ) ; anchor1 . addExpectedChild ( new TextContent ( "Home" ) ) ; body . addExpectedChild ( anchor1 ) ; Tag link1 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link1 ) ; link1 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor2 = new Tag ( "a" ) ; anchor2 . addExpectedAttribute ( "href" , ".*MockWebApplication.*" ) ; anchor2 . addExpectedChild ( new TextContent ( "Home" ) ) ; link1 . addExpectedChild ( anchor2 ) ; Tag link2 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link2 ) ; link2 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor3 = new Tag ( "a" ) ; anchor3 . addExpectedAttribute ( "href" , "Page1.html" ) ; anchor3 . addExpectedChild ( new TextContent ( "Home" ) ) ; link2 . addExpectedChild ( anchor3 ) ; Tag link3 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link3 ) ; link3 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor4 = new Tag ( "a" ) ; anchor4 . addExpectedAttribute ( "href" , ".*MockWebApplication.*" ) ; Tag span = new Tag ( "span" ) ; anchor4 . addExpectedChild ( span ) ; span . addExpectedChild ( new TextContent ( "Home" ) ) ; link3 . addExpectedChild ( anchor4 ) ; Tag link4 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link4 ) ; link4 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor5 = new Tag ( "a" ) ; anchor5 . addExpectedAttribute ( "href" , "Page1.html" ) ; anchor5 . addExpectedChild ( new TextContent ( "Home" ) ) ; link4 . addExpectedChild ( anchor5 ) ; link4 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag link5 = new Tag ( "wicket:link" ) ; link4 . addExpectedChild ( link5 ) ; link5 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor6 = new Tag ( "a" ) ; anchor6 . addExpectedAttribute ( "href" , ".*MockWebApplication.*name=test&amp;id=123" ) ; anchor6 . addExpectedChild ( new TextContent ( "Home" ) ) ; link5 . addExpectedChild ( anchor6 ) ; link5 . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag link6 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link6 ) ; Tag anchor7 = new Tag ( "a" ) ; anchor7 . addExpectedAttribute ( "href" , "Page1.html" ) ; anchor7 . addExpectedChild ( new TextContent ( "Home" ) ) ; body . addExpectedChild ( anchor7 ) ; Tag link7 = new Tag ( "wicket:link" ) ; body . addExpectedChild ( link7 ) ; Tag anchor8 = new Tag ( "a" ) ; anchor8 . addExpectedAttribute ( "href" , ".*MockWebApplication.*wicket.markup.html.link.subdir.Page1" ) ; anchor8 . addExpectedChild ( new TextContent ( "Home" ) ) ; body . addExpectedChild ( anchor8 ) ; Tag link8 = new Tag ( "link" ) ; <START_BUG> link8 . addExpectedAttribute ( "href" , "test.css" ) ; <END_BUG> body . addExpectedChild ( link8 ) ; Tag anchor9 = new Tag ( "a" ) ; anchor9 . addExpectedAttribute ( "href" , "//root//test.html" ) ; anchor9 . addExpectedChild ( new TextContent ( "Home" ) ) ; body . addExpectedChild ( anchor9 ) ; Tag anchor11 = new Tag ( "a" ) ; anchor11 . addExpectedAttribute ( "href" , ".*MockWebApplication.*wicket.markup.html.link.Page1" ) ; anchor11 . addExpectedChild ( new TextContent ( "Home" ) ) ; body . addExpectedChild ( anchor11 ) ; body . addExpectedChild ( new TextContent ( ".*" ) ) ; Tag anchor10 = new Tag ( "a" ) ; anchor10 . addExpectedAttribute ( "href" , "http:////www.google.com" ) ; anchor10 . addExpectedChild ( new TextContent ( "Google" ) ) ; body . addExpectedChild ( anchor10 ) ; validator . addRootElement ( html ) ; return validator . isDocumentValid ( document ) ; } }

Fix:
link8 . addExpectedAttribute ( "href" , "wicket//markup//html//link//test.css" ) ;